Regulatory Aspects of Gene Transfer Medicinal Products · Retroviruses : HIV/ SIV and HERV/ PERV Gene Therapy : AIDS and Tumour ... • theoretical risk of insertional oncogenesis

PaulPaul--EhrlichEhrlich--InstitutInstitutFederal Agency for Sera and Vaccines

Regulatory Aspects of Gene Transfer Medicinal Products

• Introduction and Definition

• Regulatory Requirements

• State of the Art

PD Dr. Christian J. Buchholz Div. of Medical Biotechnology, Paul-Ehrlich-Institut, 63225 Langen, GermanyE-mail: [email protected]

Bonn, 16.06.2004


Regulation & Research combined in the Divisions at PEI

Bacteriology

Virology

Immunology

Allergology

Med. Biotech.

Hematology

Vet. Medicine

Safety


Basic ResearchRetroviruses : HIV/ SIV and HERV/ PERV Gene Therapy : AIDS and Tumour Cell Therapy : Intracellular Signaling Pathways

Biotech Companies

Manufacture and Clinical Trials of Advanced Therapy

MP

Licensing of Gene and Cell Therapeutic Products

Legal Framework

Approval of Clinical Trial Applications

Division ofMedical Biotechnology

Activities in the Division of Medical Biotechnology

Scientific Advice


Innovative Innovative biotechnologybiotechnology productsproducts

Gene Transfer

MPs

HumanSomatic

Cell TherapyMPs

CellularBlood MPs

XenogeneicCell Therapy

MPs

Immuno-logicals


Innovative Innovative biotechnologybiotechnology productsproducts

• Why are they special?

• Mechanism of action is based on new insights into the molecular biology of cells and micro-organisms (molecular biology).

• Use in medicine is evidence-based.

• They pose new safety problems which are not generally foreseeable due to lack of experience in human use.

• Experience is very limited, e.g. some adverse reactions may only be observed during use in a high number of patients.

• Regulators and biomedical expertise to use them in clinical trials, to manufacture and to regulate them is very limited.


delivery system

genetically modified cell

Gene Transfer Medicinal Products (GT-MPs)

expression construct

mRNA

therapeutic protein

therapeutic gene


ex vivo in vivo

Gene transfer

Reinfusion ofmodified cells (autologous orallogenic)

Direct application:

viral vector

non-viral vector

naked DNA

microorganisms

Explantation oftarget cells

Gene Gene TransferTransfer MedicinalMedicinal ProductsProducts((preventivepreventive, , therapeutictherapeutic, , inin--vivovivo diagnosticdiagnostic useuse))


Genes used in gene transfer medicinal products

Monogeneic inherited disease• normal cell IL2R, ADA, gp55phox SCID-X1, ADA-SCID, CGD

Cancer• cytokine IL-2, GM-CSF tumor vaccines (cells)• tumor-specific tyr (melanoma) therapeutic tumor vaccines

antigens• tumor-suppr. p53 apoptose-induction (tumor cells)• suicide HSV-tk, CD GvH/leukemia, donor lymphocte killing

Cardio-vascular disease• growth factor FGF-4 myocardium repair• signaling NOX cell growth inhibitor

Infectious disease• ribozyme Ri HIV therapy

• antigenic microbial (e.g. HIV) preventive vaccines (inf. disease)


Legally required testing provisions Legally required testing provisions for advanced therapy medicinal productsfor advanced therapy medicinal products

(dossier for licensing application)(dossier for licensing application)

Annex IAnnex Iofof DirectiveDirective 2001/83/EC 2001/83/EC

as as amendedamended bybyDirectiveDirective 2003/63/EC2003/63/EC

• Technical requirements will have to be met with increasing stage of clinical testing and manufacture.

• CTD: Common Technical Document;simplified version for advanced biotechnology products.

• Establishment of the plasma (PMF) and the vaccine antigen master file (VAMF).


Gene therapy medicinal productsGene therapy medicinal products

• Annex I Directive 2001/83/EC, Part IV.

• For the purposes of this Annex, gene therapy product shall mean

• a product resulting from a set of processes aimed at the transfer, to be performed either in vivo or ex vivo,

• of a prophylactic, diagnostic or therapeutic gene (i.e. a piece of DNA),

• to human cells and its subsequent expression in vivo.

• The gene transfer involves an expression system contained in a delivery system known as a vector, which can be of viral, as well as non-viral origin. The vector can also be included in a human or animal cell.

• Conditionally replication competent adenovirus included: viral genome is the therapeutic gene.

• Live virus vaccines not included, but DNA vaccines and vectored vaccines forpreventive measures are included.


Definition of innovative Definition of innovative biotechnologybiotechnology productsproducts in in thethe AMGAMG

theoretischestheoretischesRisikoRisiko


Regulatory Requirements for GTRegulatory Requirements for GT--MPsMPs

Annex IAnnex Iofof DirectiveDirective 2001/83/EC 2001/83/EC

European Note for guidanceEuropean Note for guidanceon the quality, preclinical and clinical aspects of

gene transfer medicinal products (CPMP/BWP/3088/99)


Starting material and active substance: examples

• starting materials: materials from which the active substance is manufactured such as,• gene of interest, • expression plasmids, • cell banks and • virus stocks or non viral vector;

• active substance:• recombinant vector, • virus, • naked or complexed plasmids, • virus producing cells, • in vitro genetically modified cells.


• Information shall be provided on the relevant characteristics of the gene therapy medicinal product including

• its expression in the target cell population

• Information concerning the • source, construction, characterisation and verification

of the encoding gene sequence including its • integrity and • stability shall be provided

• The complete sequence shall be provided of the • therapeutic gene, (other genes) • regulatory elements and the • vector backbone

Technical requirements for licensing: expression, development genetics, sequences


• Information shall be provided concerning the characterisation of the

• vector used to transfer and deliver the gene,

• Its physico-chemical characterisation and/or

• Its biological/immunological characterisation.

• For medicinal products that utilise a micro-organism such as bacteria or viruses to facilitate gene transfer (biological gene transfer), data shall be provided on the

• pathogenesis of the parental strain,

• tropism for specific tissues and cell types and the

• cell cycle-dependence of the interaction.

• For medicinal products that utilise non-biological means to facilitate gene transfer,

• the physico-chemical properties of the constituents individually and in combination shall be provided.

Technical requirements for licensing: vector characterisation and source


• The principles for cell banking or seed lot establishment and characterisation shall apply to gene transfer medicinal products as appropriate.

• The source of the cells hosting the recombinant vector shall be provided and documented:

• characteristics of the human source such as age, sex,

• results of microbiological and viral testing,

• exclusion criteria and

• country of origin.

Technical requirements for licensing: cell source and banking


• organ and tissue distribution of transgene, persistence, expression over time

• exclusion of germ line transmission and environmental risk

• physiological consequencesof gene expression

• include functional end point in vivo

• it may be necessary to identify or develop new animal models.

Toxicity studies


• absence of germ line transfer

• spread into other tissues

• antibodies against vector, vector-producing cell orgenetically modified cell

• absence of replication competentvector-derived virus (shedding)

Biological Monitoring


ethics committee

opinion

Clinical trial approval(after applying European GCP Directive )

member state competent authority

clinical trial

approval

marketing authorisation,centralised procedure

60 days(90 + 90 days)

60 days(90 + 90 days)


State of the ArtState of the Art


~ 4.000 patients have been treated with GT-MPs,about 600 in Europe (260 in Germany)

PaulPaul--EhrlichEhrlich--InstitutInstitutFederal Agency for Sera and Vaccines1994 1995 1996 1997 1998 1999 2000

Number of clinical GT trials in Europe: consolidation(examplified by the development in Germany)

2

4

7 78

11 10

2001

4

2002

3

2003

5

- general economic situation- less industrial confidence in GT product success- misinterpretation of regulatory action following SCID-X1 leukemias- still constant clinical research in academia


Cancer, cardio-vascular, monogeneicand infectious diseases are the main disease targets


Most trials are phase I or I/II, few are phase IIIMost trials are phase I or I/II, few are phase III


Disease or other application No.Cancer (immunotherapy) 22

Cancer (non immunotherapy) 17Infectious disease (all HIV) 7

Monogenic inherited disorders 1Cardio-vascular disease 5

Marker gene transfer 5Others, e.g. rheumatoid arthritis 1

69 clinical GT notifications were submitted,58 clinical GT trials have been “approved” in Germany

Deutsches Register für Somatische Gentransferstudienhttp://www.zks.uni-freiburg.de/dereg.html


Gene Gene therapytherapy of of cancercancer

Ex vivo In vivo Gamma-retroviral

vector

Adenoviral vector

Naked nucleic

acid

Packaged nucleic

acid

Poxviral vector

Immuno-therapy

14 7 3 1 2 12 3

Non Immuno-therapy

4 13 4 10 3


• SCID-X1 gamma-c-chain(IL-2R) / 10 of 11 babiescured*

• Peripheral arteryocclusive disease

Vascular endothelialgrowth factor (VEGF)

i.m./ improved plasmid DNA vascularization

• Head and Conditionally replicating adenovirus,

tumor cells local tumor neck tumors no transgene regression

• Leukemia, Herpes simplex virusthymidine kinase (HSV-tk)

T cells / succesful graftgraft versus retroviral vector versus host treatmenthost treatment

• Hemophilia B Factor IX i.m./ improved plasmaAAV vector levels

Adenosinedeaminasedeficiency

Adenosine deaminasegene (ada)

blood stem cells/retroviral vector

2 patients cured

*2 patients developed lymphoproliferative disease due to vector integration

•

blood stem cells/retroviral vector

Clinical progress in gene therapy


Nature Biotechnology, 2004


Gene Therapy of X- SCID

„Severe Combined Immunodeficency“• defect in T- and B-cell development• highly sensitive towards infections

Genetic defect in γC-chain• Cytokin receptor mutated or absent• different ligands (IL-2, -4, -7, -9, -15, -21)

Fischer et al., 2002, Nature Rev Immunol. 2, 615


Ex vivo gene transfer and SCID-X1 gene therapyFischer et al., 2002

• investigator-driven approach

• mostly children < 1 year oldwith no available matched donor

• retroviral modification of CD34+ bone marrow cells (~2x108 cells per kg)

• MLV-derived replication-incompetent vector(MLV(ampho) or MLV (GaLV))

• theoretical risk of insertional oncogenesis


Cavazzana-Calvo et al., 2000

9 of 10 patients but.... P4 and P5 treated at < 3 months of agedeveloped lymphoproliferative disease


p-onc gene over-expression due to chromosomalintegration of the retroviral expression vector

over-expressedproto-oncogeneLMO2

enhancer effect

vector expressingthe γc chain gene

γγc c --chain genechain gene


Regulatory responses to leukemia-cases in 2002-2003


Lessons learned from insertional oncogenesis

• Seems to be a practical issue only for SCID-X1 gene therapy, not others.

(2 of 11 babies developed leukemias, whereas in more than 3000 other patients treated with retroviral vectors tumor induction was not observed)

• Points at necessity to check absence or level of chromosomal integration for expression vectors able to enter the nucleus of cells.

Remember: 10 of 11 babies cured!Two leukemia babies successfully treated by chemotherapy!


• Lentiviral vectors • human, primate or others• manufacture (transient or stable vpcs)• level of RCV testing• prerequisites of first use in humans

• Adenoviral vectors• understanding toxicity

(Gelsinger case!)

• Plasmid DNA• absence of resistance genes• increased dosage, absence of integration

Interesting developments (and problems!)in human gene transfer (1)


• Cell targeting vectors• replicating cell targeting MLV• tumor cell ablation (repl. adenov.)

• Tumors induced following LNGFR-expression via MLV-derived vector in CD34+ cells (mice)

• Insertional oncogenesis in SCID-X1 trial• vector integration near LMO2 gene• map integration sites for retroviral and AAV vectors

Interesting developments (and problems!)in human gene transfer (2)


BalancingBalancing riskrisk and and benefitbenefit in in genegene therapytherapy


Regulatory groups in clinical gene transfer

• National competent authorities (FDA, MCA, PEI, AFSSAPS, others)

• National central expert or ethics committees (RAC, GTAC, Commission of Somatic Gene Therapy, others)

• International groups• WHO Clinical Gene Transfer Monitoring Group• CPMP Gene Therapy Expert Group (GTEG) at EMEA• ICH Gene Therapy Discussion Group• WGs at NIBSC• Euregenethy• ASGT and ESGT Ethics Groups


ScientificScientific adviceadvice

• With a view to licensing via the centralized procedure: • EMEA

• In members states:

• expert authorities

• central ethics or expert committees

Documents

Regulatory Aspects of Gene Transfer Medicinal Products · Retroviruses : HIV/ SIV and HERV/ PERV Gene Therapy : AIDS and Tumour ... • theoretical risk of insertional oncogenesis